package JUtils.encrypt;

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;


/**
 * AES加解密
 *
 * @Author:chenssy
 * @date:2016年5月21日 上午9:01:41
 */
class AESUtils {

  /**
   * 默认秘钥
   */
  protected static final String KEY = "NOPO3nzMD3dndwS0MccuMeXCHgVlGOoYyFwLdS24Im2e7YyhB0wrUsyYf0";

  /**
   * AES解密
   *
   * @param encryptValue
   *     待解密内容
   * @param key
   *     秘钥
   * @author:chenssy
   * @date : 2016年5月21日 上午9:48:12
   */
  protected static String decrypt(String encryptValue, String key) throws Exception {

    return aesDecryptByBytes(base64Decode(encryptValue), key);
  }

  /**
   * AES加密
   *
   * @param value
   *     待加密内容
   * @param key
   *     秘钥
   * @author:chenssy
   * @date : 2016年5月21日 上午9:48:42
   */
  protected static String encrypt(String value, String key) throws Exception {

    return base64Encode(aesEncryptToBytes(value, key));
  }

  private static String base64Encode(byte[] bytes) {

    return Base64Utils.encrypt(bytes);
  }

  @SuppressWarnings("static-access")
  private static byte[] base64Decode(String base64Code) throws Exception {

    return base64Code == null ? null : new Base64Utils().decrypt(base64Code);
  }

  private static byte[] aesEncryptToBytes(String content, String encryptKey) throws Exception {

    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    kgen.init(128, new SecureRandom(encryptKey.getBytes()));

    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));

    return cipher.doFinal(content.getBytes("utf-8"));
  }

  private static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {

    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    kgen.init(128, new SecureRandom(decryptKey.getBytes()));

    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
    byte[] decryptBytes = cipher.doFinal(encryptBytes);

    return new String(decryptBytes);
  }

}
